Process of producing acid monocalcium phosphate.



R. STEWART.

PROCESS OF PRODUCING ACID MONOCALCIUM PHOSPHATE.

APPLICATION FILED JUNE 11. 1914.

1,137,0 v Patented May 4, 1915.

3] wuzntoz attorney ITED TATE PATENT QI FWEQ nonnnr srnwnnr, or LoeAiw-, Umn.

LZROCESS- 0F PRODUCING ACID MONOCALCIUM PHOSPHATE.

menace.

Specification of Letters Patent.

Patented May 4, 11915.

Application filed June 17, 1914. Serial No. 845,711.

Utah, have invented certain new and useful Improvements in Processes of Producing Acid Monocalcium Phosphate, of which the following is a specification.

My invention relates to a process of producing, isolating and recovering acid monocalcium phosphate by the treatment of phosphate rock or tri-calcium phosphate with smelter smoke, in the presence of steam or water vapor.

An important object of the invention is to provide a process for the production of acid mono-calcium phosphate from tri-calcium phosphate, by the employment of smelter smoke as a reagent, whereby the sulfur dioxid and tri-oxid in the smelter smoke are removed by being converted into calcium sulfate.

In the accompanying drawings forming a part of this specification and in which like numerals are employed to designate like parts throughout the same, Figure 1 is a central longitudinal sectional view through apparatus within which my process may be advantageously practised, and, Fig. 2 is a partly diagrammatic view of an electrical oxidizing apparatus.

In accordance with my process, phosphate rock or tri-calcium phosphate is heated with smelter smoke in the presence of steam or water vapor, whereby acid mono-calcium phosphate and acid calcium sulfite are produced as illustrated in the following equation Ca PO )2+4S02+4H-,0:

( a o -r n s oz The acid mono-calcium phosphate acts upon and decomposes part of the normal calcium sulfite with the production of dicalcium phosphate as shown in the following equation:

a on F After this has been done, the solution may be readily concentrated by evaporation,

,without the decomposition of the acid monocalciurn phosphate, whereby the same may be readily recovered.

In the drawings, wherein for the purpose of illustration is shown apparatus in connection with which my process may be advantageously practised, the numeral 5 designates a longitudinally inclined rotatable tube, preferably formed of iron and having its inner surface covered with refractory material 6. This tube is rotatably supported in any well known or preferred manner, and receives rotation from a pinion 7, engaging an annular gear 8, rigidy secured to the exterior of the tube. Disposed near the upper end of the tube 5 is a vertical stationary tube 9, for holding the phosphate material or rock, which is preferably suitably broken before being fed therein. This phosphate rock is fed from the lower end of the vertical tube 9 into the upper end of the inclined rotatable tube 5 by a spiral conveyer 10, driven by any suitable means.

The numeral 11 designates a sprinkler pipe for discharging water upon the phosphate rock in the vertical tube 9.

The numeral 12 designates a steam supply pipe discharging into the tube 5 in the presence of the phosphate rock.

The numeral 13 designates a relatively large pipe, discharging smelter smoke into the tube 5 in the presence of the phosphate rock. The tube 5 is heated by any suitable means, such means beingillustrated the form of a blow pipe burner 14, discharging electricallyoperated oxidizing apparatus.

In Fig. 2, I have shown a somewhat diagrammatic View of an oxidizing apparatus, the same comprising a shell 16, formed of iron or the like and carrying interior contacts 1.7, adapted to be engaged and disenthe-shell 16 and fed into a suitable evaporating pan (not' shown), where the same is heated and concentrated by evaporation.

It is to be understood that the form of my process herein described is to be taken as a preferred example of the same, and that various changes in the practice of the steps thereof may be resorted to without departing from the spirit of theinvention or the subjecting the solution thus obtained to the scope of the subjoined claims.

Having thus described my invention, I claim 1. The vherein described process, which consists in subjecting phosphate rock to the action of smelter smoke in the presence of steam, whereby acid mono-calcium phosphate and acid calcium sulfite are produced,

action of an oxidizing agent, and recovering the acid mono-calcium phosphate in the so- 40 lutionjwithout decomposing the same.

2. The herein described process, which consists in subjecting phosphate rock to the action of smelter smoke in the presence ofsteam whereby acid mono-calcium phosphate and acid calcium sulfite are produced, subjecting the solution thus obtained to the actionrof an oxidizing electric current, and

recovering, the acld mono-calcium phosphate 1n solution without decomposing the same. Y

gaged by revolving contact arms 18', carried 3. The herein described process, which consists in subjecting phosphate and acid calcium sulfite are produced, oxidizing the acid calcium sulfite whereby it is converted into calcium sulfate and sulfuric acid, and concentrating the solution for recovering the, acid mono-calcium phosphate WitllOllt decomposing the same.

4. The .herein described process, which consists in subjecting phosphate rock to the action of smelter smoke in the presence of heat and water whereby acid mono-calcium phosphate and acid calcium sulfite'are produced, oxidizing the acid calcium sulfite, and recovering the acid mono-calcium phosphate, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses, a ROBERT STEWART. Witnesses:

phosphate rock to the action of smelter smoke in the presence of heat and water whereby acid mono-calcium 55 

